Reciprocating rod packing



April 9, 1963 c. L. SHARP RECIPROCATING ROD PACKING 2 Sheets-Sheet 1Filed July 16, 1959 Figa-Z INVENTOR. CHf-s ne@ L. SHAQP April 9, 1963 c.L. SHARP 3,084,946

RECIPROCATING ROD PACKING Filed July 16, 1959 2 Sheets-Sheet 2 INVENTOR.CHf-sTf-Q L, SHAW A TTOPA/EY United States Patent O 3,084,946RECIPROCATING ROD PACKING Chester L. Sharp, Tulsa, Okla., assiguor toDouglas O. Johnson and Leo W. Fagg, co-partners, doing business asJohnson-Fogg Engineering Company, Tulsa, Okla.

Fiied July 16, 1959, Ser. No. 827,49() 3 Claims. (Cl. 277-121) Thisinvention relates to improvements in stuing box packing devices.

In a typical oil well pumping application, a string of sucker rods isreciprocated in well tubing `by a surface pumping unit. This actionoperates a pump at the bottom of the well to lift oil up the tubing tothe surface of the earth. At the surface a T fitting is provided,terminating the tubing string, to convey the produced oil to properstorage facilities. ln order to force the produced oil into the conduitleading to the storage tank, `and prevent the oil from discharging outthe top of the T, a suitable stuffing box must be provided.

A machined finished rod, usually termed a polished rod, terminates thesucker rod string, and is provided to reciprocate through the stuiiingbox. The stuffing box has two primary functions. First, it must act tokeep the produced oil within the tubing and conduit or lead lineconnecting to the storage tank, and second, it must be so constructed`as to oifer the least frictional resistance to the oscillatory motionof the polished rod. A stutiing box which requires the packing becompressed tightly against the polish rod to prevent leaking causes agreat loss of horsepower in frictional energy, as well as increasing thewear and decreasing the life of the stuffing box packing.

Much `of the crude oil produced by pumping wells comes from the earthmixed with varying quantities of paraiiin and contaminated water. Thewater usually contains a high concentration of `dissolved salts andminerals. On each down stroke of the pumping unit a greater part of thepolished rod enters the tubing below the stuing box and contacts theproduced oil and contaminated water. On the up stroke of the pumpingunit a greater part of the polished rod rises above the stutiing boxwhere it is exposed to the drying elfects of the atmosphere. In thismanner there is a strong tendency for the deposition of scale and ruston the polished rod. Naturally, this scale and rust accumulationdestroys the uniform machined surface originally given the polished rod,with the result of greatly reduced packing life. The commonly usedrelatively thin, soft, resilient packing necessary to form a leakproofseal around the polished rod does not oder sufficient coercive effect toprevent this scale and rust formation. Etorts to force the packing intotighter gripping relationship causes buckling and failure.

A great expense is encountered in the oil industry in maintainingstuffing boxes. In most instances a pumper must visit each well at leastOnce a day to determine that the stuffing box has not permitted oilleakage which drains upon fittings etc. around the well, as well lasupon the surface of the earth where it has a strong sterilant action,rendering soil eifete.

It is therefore `an object of this invention to provide improvements instuhing boxes and stufiing box packing, which overcome problems existingwith prior apparatus.

Another object of this invention is to provide a frustoconical shapedpacking `for stuffing `boxes having a lowfriction, high surface areacontact with polished rods.

Another object of this invention is to provide an arrangement of stuingbox packing which will afford greater lateral support to truste-conicalshaped packing.

Another object of this invention is to provide means associated withstutling box packing to prevent the formation of scale and otherabrasive surface discontigurations on polished rods.

These and other objects of this invention will be more apparent fromfurther reading of the following description and claims when taken inconjunction with the drawings of which:

FIG. l is a side view of a stufng box taken partly in vertical sectionshowing the arrangement of the packing of this invention.

FIG. 2 is an enlarged view of the packing of this invention shown inassociation with `a polished rod. The packing is shown in verticalcross-section.

FIG. 3 is a cross-sectional view of a modiiied stufling box showing thepacking of this invention as used in conjunction with an improved typepacking seat.

FIG. 4 is a cross-sectional view of an alternate arrangement of thisinvention showing an integrally formed wire mesh disposed to contact thepolished rod surface.

Referring first to FIG. l, a typical stutiing box body is shown having`an integrally cast neck 12 with threads 14 for connection into the topof a typical pumping T, not shown. An outer follower 16 and an innerfollower 18 are provided as a means by which a proper pressure may beapplied to the packing to prevent the stuiling box for leaking.Integrally cast flange 20 on the stulng box `body 10 is provided forreceiving studs 22. Ears 24 and 26, integrally cast with the outerfollower 16 and inner follower 18, respectively, are provided, havingholes through which threaded studs 22 protrude. By turning nuts 28 onstuds 22 the tension of the outer follower 16 and inner follower 18 maybe varied.

A polished rod 30 extends through the stufiing box 10 to be connected atits lower extremity with a string of sucker rods, not shown. The upperextremity of the polished rod 30 would connect to the surface pumpingunit, also not shown.

An important feature of this invention concerns the novel configurationof the packing, which is best disclosed in FIG. 2. The packing iscomposed of resilient, oil resistant material, such as a syntheticrubber produced and sold under the trademark Hycar and comprises twoportions-mst, a lower frusto-conical packing ring 34, and second, one ormore upper packing rings 36. The upper packing rings 36 are of afrusto-conical shape and can be molded in this shape or cut from flatand cylindrical material. The frusto-conical shape of the upper packingrings 36 is achieved from hat material by rst cutting a disc and thenextracting a wedge-shaped segment at the radial split 38.

The lower packing ring 34 has a thick shoulder section 40 extendingthrough the major portion of the length of the ring which serves toafford a larger contact area with the polished rod 30 and also giveslateral support to the upper packing rings 36. Others have providedstuing box packing utilizing frusto-conical shaped packing rings whichhas worked successfully, but their failure to provide lateral supporthas resulted in a reduced life of the packing and a higher degree ofstuffing box failures.

Flat surface areas 42 are provided at the peak portions Where the upperpacking rings 36 contact the polished rod 30 to afford greaterprotection from huid leakage. Each area 42 may be extended by forming acircumferential lip 43 around the lower end of the area 42 if desired.Also, a flat skirt area 44 is provided on the upper packing rings 36 andlower packing ring 34 around the lower peripheral portions thereof wherecontact is made with the stuilng `box body 10 to assure a more efficientseal.

The top surface 45 of the peak portion of each of the packing rings 34and 36 is formed transversely with respect to the areas 42 and 44 toprovide lubricant cavities 46 between adjacent rings and assure constantlubrication of the polished rod 30. This multiplicity of lubri cantcavities collects and holds oil applied to the stuffing box l!) anddistributes it evenly on the surface of the polished rod 30.

The present packing construction may also be used in an open type ofstuffing box (see FIG. 3) having an internal diameter of a size for thepassage of various tools et-c. through the box. A typical stutiing `boxof this type is illustrated in FIG. 3 and comprises a tubular housing 43slightly reduced in diameter at 49 to form a tubing section St) which inturn connects with the well tubing. A line pipe section 52 extendstransversely from the tubing section 50 for connection with a ow line toconvey produced crude oil to storage facilities. It will `be apparentthat the smallest internal diameter of the housing 48 is in the tubingsection 50 which is normally the same diameter as the well tubing topermit the passage of various tools (such as the subsurface pumping unitused in the lower end of the well tubing) through the stuffing box onlyby removing the packing. With such a stutling box construction, it iscommon practice to use a metal seating ring 54 in the portion 49 of thehousing 48 to support the packing. The upper end 56 of the seating ring54 is tapered downwardly and outwardly to guide the packingconcentrically in the housing 48, and the lower end 58 of the ring 54 isrounded to seat on the mating reduced diameter portion 49 of the housing43. A flange 61) is normally formed around the ring 54 and is of a sizeto slidingly fit in the housing 48 to form a shoulder on which thepacking rnay rest. It will also be understood that the stuffing boxshown in PIG. 3 also has a suitable follower assembly similar orequivalent to the followers 16 and 13 shown in FIG. 1 to hold thepacking in place in the housing 48.

When using the present packing assembly in a stuffing box of the typeshown in FIG. 3, the lower ring 34 ts closely over the seating ring 54to efhciently support the upper packing rings 36. It will be observedthat the lower face 62 of the shoulder section 40 of the ring 34 isformed at a right angle to the area 44 to rest on the upper end of thering 54 and facilitate the support of the upper packing rings 36 againstcollapse. Also, the area 64 of the ring 34 between the hat portion 62and lower end of the skirt forming the flat area 44 is tapered toconform with the tapered portion 56 of the ring 54 and prevent collapseof `the skirt when excessive pressure is applied on the packing. Theflat areas 44 of all the rings 34 and 36 seal against the innerperiphery of the housing 48 in the same manner as previously described.

Another embodiment of this invention is shown in FIG. 4. The lowerpacking ring 34 is provided with an integrally formed abrasive innersurface 66. The abrasive inner surface scours the polished rod, notshown, as it reciprocates within `the stuffing box. As rust and scaletend to form, the scouring, attrition action of the abrasive innersurface prevents accumulations which would deform the surface of thepolished rod and ultimately cause increased wear on the upper packingrings 36.

The material comprising the abrasive inner surface 66 is of a hardnessless than the polished rod and is preferably a `metallic meshed or wovenmaterial, such as copper, formed integrally with the lower packing ring34 during the vulcanizing or molding process. However, any materialhaving a hardness greater than the resilient material forming the ring34, but a hardness less than the polished rod, will provide a beneficialabrasive action.

As the abrasive inner surface 66 wears away, the tension applied on thestuting box packing, as by tightening outer follower 16 or innerfollower 18, will urge the abrasive inner surface 66 against the polishrod 30 to maintain a continuous scouring action over a long period.

Although this invention has been described in the kit! manner in whichit would be applied to oil well pumping, it is within the purview ofthis invention that the principles involved are equally applicable toany type of reciprocating rod packing device.

Although I have described this invention with a certain degree ofparticularity it is manifest that many changes may be made in thedetails disclosed without departing from the spirit or scope of theinvention as taught by the claims.

l claim:

1. A reciprocating rod packing device comprising:

an annular body surrounding thc rod having an upper end and a lower endand arranged concentrically around the rod;

an upper, hollow, substantially frusto-conical resilient packing ring inthe body around the rod having a lower and outer peripheral surfaceengaging the inner surface of the body and having its inner and uppercylindrical surface at its peak portion sealingly engaging the rod, theupper and lower surfaces of said peak portion joining the upper andlower ends of said cylindrical surface being extended horizontally fromthe rod to form a horizontally' extending flexible lip sealinglyengaging the rod;

follower means adjustably secured to the upper end of the body andarranged to force the inner and outer portions of the packing ringdownwardly in the body to increase the seal of the peak portion of thepacking ring around the rod and accommodate wear of the peak portion ofthe packing ring; and

a lower, resilient supporting packing ring in the body around the rodunderneath the upper packing ring to prevent collapse of the upperpacking ring, said lower packing ring having a frusto-conical upper andouter surface acting with the inner frustoconical surface of the upperpacking ring from the lower outer end of the upper packing ring intoproximity with the peak portion of the upper packing ring, and having acylindrical inner surface in contact with the rod from the lower end ofthe upper packing ring into proximity with the peak portion of the upperpacking ring to support the upper packing ring from the rod and preventcollapse of the upper packing ring, the upper end of said lower packingring being substantially flat and terminating in downwardly spacedrelation from the peak portion of the upper packing ring to provide alubricating reservoir between the upper and lower packing rings aroundthe rod and to provide a space for downward flexing of the peak portionof the upper packing ring upon downward movement of the follower means.

2. A reciprocating rod packing device as defined in claim 1characterized further to include a plurality of said upper packingrings.

3. A reciprocating rod packing device as defined in claim lcharacterized further to include an abrasive material formed integrallyin the cylindrical inner surface of the lower packing ring to scrape therod.

References Cited in the tile of this patent UNITED STATES PATENTS196,119 Holt Oct. 16, 1877 1,845,683 Saunders Feb, 16, 1932 2,006,529Wheeler July 2, 1935 2,056,687 Moseley Oct. 6, 1936 2,564,912 McKissickAug. 21, 1951 2,634,145 Monahan Apr. 7, 1953 2,833,572 Moseley May 6,1958 2,892,643 Moseley inne 30, 1959 2,994,549 Tschappat Aug. 1, 19613,013,831 'Tschappat Dec. 19, 1961

1. A RECIPROCATING ROD PACKING DEVICE COMPRISING: AN ANNULAR BODYSURROUNDING THE ROD HAVING AN UPPER END AND A LOWER END AND ARRANGEDCONCENTRICALLY AROUND THE ROD; AN UPPER, HOLLOW, SUBSTANTIALLYFRUSTO-CONICAL RESILIENT PACKING RING IN THE BODY AROUND THE ROD HAVINGA LOWER AND OUTER PERIPHERAL SURFACE ENGAGING THE INNER SURFACE OF THEBODY AND HAVING ITS INNER AND UPPER CYLINDRICAL SURFACE AT ITS PEAKPORTION SEALINGLY ENGAGING THE ROD, THE UPPER AND LOWER SURFACES OF SAIDPEAK PORTION JOINING THE UPPER AND LOWER ENDS OF SAID CYLINDRICALSURFACE BEING EXTENDED HORIZONTALLY FROM THE ROD TO FORM A HORIZONTALLYEXTENDING FLEXIBLE LIP SEALINGLY ENGAGING THE ROD; FOLLOWER MEANSADJUSTABLY SECURED TO THE UPPER END OF THE BODY AND ARRANGED TO FORCETHE INNER AND OUTER PORTIONS OF THE PACKING RING DOWNWARDLY IN THE BODYTO INCREASE THE SEAL OF THE PEAK PORTION OF THE PACKING RING AROUND THEROD AND ACCOMMODATE WEAR OF THE PEAK PORTION OF THE PACKING RING; AND ALOWER, RESILIENT SUPPORTING PACKING RING IN THE BODY AROUND THE RODUNDERNEATH THE UPPER PACKING RING TO PREVENT COLLAPSE OF THE UPPERPACKING RING, SAID LOWER PACKING RING HAVING A FRUSTO-CONICAL UPPER ANDOUTER SURFACE ACTING WITH THE INNER FRUSTOCONICAL SURFACE OF THE UPPERPACKING RING FROM THE LOWER OUTER END OF THE UPPER PACKING RING INTOPROXIMITY WITH THE PEAK PORTION OF THE UPPER PACKING RING, AND HAVING ACYLINDRICAL INNER SURFACE IN CONTACT WITH THE ROD FROM THE LOWER END OFTHE UPPER PACKING RING INTO PROXIMITY WITH THE PEAK UPPER PACKING RINGFROM THE ROD AND PREVENT COLLAPSE OF THE UPPER PACKING RING, THE UPPEREND OF LASPE OF THE UPPER PACKING RING, THE UPPER END OF SAID LOWERPACKING RING BEING SUBSTANTIALLY FLAT AND TERMINATING IN DOWNWARDLYSPACED RELATION FROM THE PEAK PORTION OF THE UPPER PACKING RING TOPROVIDE A LUBRICATING RESERVOIR BETWEEN THE UPPER AND LOWER PACKINGRINGS AROUND THE ROD AND TO PROVIDE A SPACE FOR DOWNWARD FLEXING OF THEPEAK PORTION OF THE UPPER PACKING RING UPON DOWNWARD MOVEMENT OF THEFOLLOWER MEANS.